Revert "Fix remaining strong-mode warnings and errors in dart:io."

sdk/lib/io/socket.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.io;
 
 
 /**
  * [InternetAddressType] is the type an [InternetAddress]. Currently,
  * IP version 4 (IPv4) and IP version 6 (IPv6) are supported.
@@ skipping 550 matching lines @@
 
   /**
    * Returns the [InternetAddress] used to connect this socket.
    */
   InternetAddress get address;
 
   /**
    * Returns the remote [InternetAddress] connected to by this socket.
    */
   InternetAddress get remoteAddress;
-
-  Future<Socket> close();
-
-  Future<Socket> get done;
 }
 
 
 /**
  * Datagram package. Data send to and received from datagram sockets
  * contains the internet address and port of the destination or source
  * togeter with the data.
  */
 class Datagram {
   List<int> data;
@@ skipping 148 matching lines @@
     }
     if (address != null) {
       sb.write(", address = ${address.host}");
     }
     if (port != null) {
       sb.write(", port = $port");
     }
     return sb.toString();
   }
 }